21. How many kg of an alloy with 90% copper must be added to 6 kg of another alloy with 15% copper to
obtain an alloy that is 40% copper? (Must show Work)

40 i don’t know lololol

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in addition, millions of immigrants came to the united states during this era, seeking a better life for themselves and their families. one important result of industrialization and immigration was the growth of cities, a process known as urbanization. commonly, factories were located near urban areas.